In the case of projection applications based on the fundamentally known LARP (“Laser activated remote phosphor”) technique, a phosphor is irradiated by a laser and the irradiated light is partially converted by means of the phosphor into a wavelength-converted or frequency-converted utility light, and partially scattered back without a wavelength conversion. A primary pump light generated by the laser need not be used, or need not be continuously used, directly as utility light. In order to generate a wavelength-converted utility light that is pure during the irradiation of the phosphor, it is necessary for the pump light component of unconverted wavelength to be filtered out at this time. A rotating filter wheel with optical filters such as is known from projector applications can provide a assistance here.
If use is made of a rotating phosphor wheel in order to carry the phosphor, something which is particularly advantageous for an efficient wavelength conversion given high pump light intensities (from approximately 5 W/mm2), there is a need for a total of two rotating wheels, specifically the filter wheel and the phosphor wheel, to be synchronized with one another. This signifies a high technical outlay.